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TECHNICAL ADVISE SHEET: MOSAICS INSTALLATION TO THE HIGHEST STANDARDS Mosaic installation is important, and must be carried out to the highest standards. Grestec aims to serve a clientele capable of appreciating our product’s quality of materials and flawless installation. So we are committed to ensuring that our mosaics are easy to apply and use. This manual is intended as a complete tool, providing guidance for every kind of situation. For any queries or suggestions, please contact our Technical Department. tel. +44 345 130 2241, mail@grestec.co.uk
CONTENTS 02
Tools
03
Glass Mosaics
04
Substrate preparation
05
Installation
11
Special installation jobs
20
Swimming pools
21
Installation products
34
Material characteristics
37
Technical specifications
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INSTALLING GLASS MOSAICS: TOOLS Regardless of the type of substrate, and the adhesive and grout you will be using, it is essential to have the right equipment, and ensure that it is in good condition:
TOOTHED SPATULA
ANGLE-GRINDER WITH CONTINUOUS RING 110 DIAMOND DISC
Spatula with 10x10 mm triangular teeth for installing resilient products, or 30x30 mm teeth for laying mosaics 4mm thick. Use the smooth side of the spatula for levelling.
For cutting chips and/or sheets
POINTING TROWEL
SANDPAPER AND ABRASIVE OR DIAMOND SPONGES
For adjusting joints
For rounding off sharp edges
RUBBER-COATED PLASTERING TROWEL, CELLULOSE SPONGES AND FELT*
HELICAL STIRRER
For ensuring the adhesion of chips and removing surplus adhesive
For mixing adhesive and grout ingredients (a drill accessory, use at low speed) **to be used for all collections except Luminere Met, for which we recommend the use of a cellulose sponge only
ORDINARY OR MOSAIC WHEEL PINCERS For cutting chips to the shapes required
UTILITY KNIFE For cutting the mosaic backing
TOOTHED SPATULA
POINTING TROWEL
WHEEL PINCERS
PLASTERING TROWEL
UTILITY KNIFE
HELICAL STIRRER
ANGLE GRINDER
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INSTALLING GLASS MOSAICS: MESH/PAPER/PLASTIC MOUNTED MESH-MOUNTED MOSAICS The underside of the chips is laid straight on the adhesive. (If a protective film is applied to the mosaic sheet, it must be removed gently before installation). The mesh can be cut with an ordinary utility knife. Mesh-mounted mosaics are suitable for any use, bearing in mind that the joints tend to open out in curved areas. This needs to be corrected by cutting with the utility knife as appropriate. Benefits: It is easy to cover surfaces; the grout is applied prior to installation so there is no need to wash the mosaic; the installation process is intuitive even for unskilled installers.
PAPER-MOUNTED MOSAICS Paper-mounted mosaics are recommended for artistic materials, except for computer-aided artistic mosaics, in order to compensate for their variation in thickness, for curved walls and when covering three-dimensional objects. The mounting paper is ribbed in parallel lines, meaning that it has an installation direction. The lines allow the material to expand either vertically or horizontally. Once the expansion direction has been chosen, the mosaic must be installed accordingly. Benefits: Easy coverage of complex surfaces; the joint width is the same regardless of the curve to be covered; easy adjustment of the individual chips; better bond between chip and adhesive. Drawbacks: Once the paper has been removed, the mosaic must be washed and cleaned thoroughly to remove adhesive residues.
PLASTIC-MOUNTED MOSAICS This system has the same characteristics as the paper-mounting method. Benefits: Compared to paper-mounting, the plastic’s transparency provides a better view of the overall design during installation. Applications are the same as for paper-mounted mosaic.
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INSTALLING GLASS MOSAICS: SUBSTRATE PREPARATION BASIC PRINCIPLES Before starting installation, the condition of the surface on which the composition is to be created should be checked. The preparation process is the same for every product, regardless of the mosaic’s type, size or thickness. However, the levelling and/or waterproofing phases which follow will depend on the intended use of the work of mosaic (indoors, outdoors, swimming-pools, etc.), and it is therefore your responsibility to choose products technically and chemically suitable for the substrate.
LEVELLING The substrate must be cured or seasoned, clean, level and smooth, with no cracks or dust residues on the surface. Otherwise, the surface should be levelled using one of the specific products available on the market, which must be white to avoid interfering with the transparent colours of the mosaic. After levelling, wait for the adhesive to cure completely. Plasterboard, Aerolam, etc. surfaces must be treated with a suitable primer to ensure that the adhesive bonds to them properly.
WATERPROOFING (IF NECESSARY) Surfaces must always be waterproofed with cement mortars applied with a toothed spatula. Otherwise, it will not be possible to use cement-based adhesives. When waterproofing substrates such as fibreglass or membranes, on which a cement-based product cannot be used, contact our Technical Department on 0345 130 2241.
UNSUITABLE SUBSTRATE
PROPERLY LEVELLED SUBSTRATE
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INSTALLING GLASS MOSAICS: PREPARATION CHECKING THE MATERIAL FOR LAYING • Check the number of boxes, the production lots, the colour and the order code, for use when requesting extra materials or correcting any shortfalls. • Ensure that the quantities of adhesive and grout available are sufficient and that all essential installation tools are to hand. • Check that the packs of mosaic and adhesives have been stored in a dry place and protected from rain and damp. Notify the foreman if the materials have been damaged.
INSTALLATION AREA It is important to check that the installation area corresponds to an exact number of chips: for installation to the highest standards, the chips must not be cut unless absolutely necessary. The point at which installation starts is therefore very important, and the installer must decide whether to “adapt” the installation area if necessary by adding a thicker layer of adhesive during levelling (recommended for mosaics with chips of 20x20 mm or on small areas) or to use a pointing trowel to increase the gap between chips (mosaic with chips of 15x15 and 10x10mm). To measure the installation area, spread the sheets on it side by side “dry”.
Space between chips of 20x20mm with use of a thicker layer of adhesive
Space between chips of 10x10mm with use of a thicker layer of adhesive
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INSTALLING GLASS MOSAICS: ADHESIVES THE STARTING POINT • Before starting, it is important to draw reference lines for application of the first sheets. Refer to the layout plan if available, or check the modular sheet size. • Find the most appropriate starting point and use a straight-edge and spirit level to draw the first horizontal line to mark the first level, the height of 3 sheets above the floor. • Then draw a second line, a further 3 sheets high, starting from this line. Installation of the material must be started in the area between the 1st and 2nd levels. • Move on to install the material in the area underneath the 1st level line and complete the job by installing in the area above the 2nd level, up to the chosen height. ** To ensure even laying of the mosaic sheets, do not apply excess adhesive to the outside of the sheets.
APPLYING THE ADHESIVE Prepare the adhesive in accordance with the instructions in its technical data sheet. This will allow the production of a uniform, lump-free mixture. The adhesive must be applied to the surface for coating smoothly and evenly. Use the toothed side of the spatula. Only apply the amount of adhesive needed to cover small areas. The adhesive should never flow out-beyond the edges of the sheets being installed.
2o LEVEL
1o LEVEL
Starting point
Applying the adhesive
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INSTALLING GLASS MOSAICS: MESH-MOUNTED INSTALLATION OF MESH-MOUNTED MOSAICS Place the mesh-backed sides of the mosaic sheets directly on the layer of adhesive, pressing gently and making sure that the gap between the sheets is the same as that between the chips.
TAPPING DOWN Tapping with a rubber-coated plastering trowel allows the adhesive to penetrate between the chips. The adhesive must penetrate between the openings in the mesh and the chips and fill the gaps in the joints (indicating that the mosaic has been tapped down effectively), while leaving a thickness of about 1.5 free for the final grout. Gentle tapping can also be used for sideways corrections in the position to align the joints properly. Excess adhesive must not come out of the joints. If this happens, level the substrate better, because it is not flat. ** Remember to remove any adhesive residues from the surface of the mosaic with a damp sponge without delay.
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INSTALLING GLASS MOSAICS: PAPER/PLASTIC MOUNTED INSTALLATION OF PAPER OR FILM-MOUNTED MOSAICS
Lines are drawn on the paper on which the mosaic chips are mounted. These must always be positioned running in the same direction, generally vertical. The sheets must then be installed with the chips resting directly on the adhesive, with the paper facing towards you. Take care to ensure that the distance between sheets is correct: it must be the same as the joint between chips.
REMOVING THE MOUNTING PAPER
Before removing the mounting paper, wait until the adhesive has set and is able to hold the chips in places, which generally takes about 3 hours (it depends on various factors, such as humidity, temperature, etc....) Wipe a soft cellulose sponge wet with water across the surface several times, until the paper starts to detach from the chips. Then pull the mounting paper gently upwards along the diagonal of the sheet, keeping it as close as possible to the mosaic-covered surface. Finally, wash the adhesive residues thoroughly, several times, with a sponge dipped in water.
REMOVING THE PLASTIC MOUNTING FILM
Wait for the adhesive to set. Then pull the film gently upwards along the diagonal of the sheet, keeping it as close as possible to the mosaic-covered surface. If the chips tend to move as this is done, wait for the adhesive to set harder. Take care because the rate at which the adhesive dries and sets decreases from the edges towards the centre of the film.
TAPPING PAPER-MOUNTED MOSAIC
Tapping with a rubber-coated plastering trowel allows the adhesive to penetrate between the chips. The adhesive must penetrate between the chips and fill the gaps in the joints (indicating that the mosaic has been tapped down effectively) while leaving a thickness of about 1.5 free for the final grout. Smooth over the sheets with a pointing trowel so that the mosaic adheres perfectly and the surface is absolutely flat.
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INSTALLING GLASS MOSAICS: JOINTS ADJUSTING THE JOINTS
Before the adhesive sets completely, the gaps between chips have to be corrected, both between the sheets just installed and between the individual chips. Chips are moved closer together or apart using a pointing trowel, using a utility knife to cut through the mesh still immersed in the adhesive. The need to cut chips can be avoided by adjusting the positions of vertical or horizontal rows of chips, by varying the joints between chips (increasing or reducing them) almost imperceptibly. Clean the surface with a damp sponge to remove surplus adhesive. The mosaic is ready for grouting after 24 hours.
PREPARING EPOXY GROUT / COLOREPOXY
Mix the two components following the instructions in the label and stir to a smooth paste. The packs are pre-weighed in the correct proportions: do not modify the mixing ratio and do not add any other products (water, etc.). Follow the safety instructions provided and wear protective clothing for the face and hands throughout the grouting process.
GROUTING WITH EPOXY
Before grouting, check that the surface is perfectly dry with no residues of water or cleaning products in the joints; use a utility knife to remove any excess adhesive from the joints. Use the pointing trowel to transfer the grout to the rubber-coated plastering trowel and apply the Colorepoxy by moving the plastering trowel in lines diagonal to the chip rows, working upward and taking care to fill the entire depth of the joints. Use the edge of the plastering trowel to wipe away the surplus material. Tools and hands can be cleaned with water as long as the Colorepoxy is fresh, or mechanically or with a suitable cleaning product once it has set.
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INSTALLING GLASS MOSAICS: CLEANING CLEANING After grouting, just before the grout has totally set, start cleaning, using water and methylated spirits or if preferred a specific cleaning product (Kerapoxy Cleaner by Mapei). Dip the white felt in a container of the preferred liquid (except for the Luminere Met collection, when the cellulose sponge must be used) and rub briskly in a circular direction to remove the excess grout (by emulsifying it with the liquid) and smooth over the joints. Rinse with a sponge and clean water. To eliminate all smears and restore the mosaic’s shine, repeat this operation a few hours later, always ending by rinsing with clean water.
ROUTINE CARE For daily cleaning, we recommend the use of ordinary neutral cleaners; oils, wax and hydrofluoric, phosphoric or orthophosphoric acids or cleaners which contain them should not be used. To remove lime-scale, we suggest the use of slightly acid products; in other cases, use slightly alkaline products, always rinsing with plenty of clean water. If you decide to use a specific product, follow the producer’s instructions on the label. If correctly installed, mosaic surfaces do not have any particular problems regarding contact with water. However, frequent contact with boiling water, which could weaken the grouting, should be avoided. The use of steam cleaning appliances is therefore not recommended.
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SPECIAL INSTALLATION JOBS: SHADES, MODULAR & DECOR Open all the packs and spread the entire decoration on the ground, checking that the number of the sheets is as marked in the layout plan.
COLOUR TRANSITIONS Colour transitions consist of modules of 7-8 sheets, depending on chip size, of blends of gradually varying colours. A pack contains a whole module. The sheets are numbered and the layout plan will tell you whether the module will be vertical or horizontal, or with colours running from light to dark or vice-versa. Before installing, always draw reference lines of the surface, bearing in mind the complete colour transition.
MODULAR DECOR MOSAICS Modular Decor mosaics may consist of one or more sheets. A module is an identical, repeated pattern with features which run on from one sheet to the next. It is very important to follow the layout plan closely, because some modules are very complex. We advise you to check the portion of the module you are about to install by placing the sheets side by side on the ground or on a worktop. Before installing, always draw reference lines on the surface.
COMPUTER-AIDED ARTISTIC MOSAICS AND CUSTOMISED DESIGNS These are created with the aid of a computer, using chips of uniform size mounted on paper or mesh. It is essential to follow the installation plan provided in box no 1; if it is not there, always ask for a copy and never start installation without this essential aid, even if the design looks simple to you.
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SPECIAL INSTALLATION JOBS: GOLD MOSAICS GOLD MOSAICS The Luminere (MOD) collection comes in three sizes, 10x10, 15x15 and in flat and corrugated finishes. The chips are produced by placing a sheet of yellow or white 24 carat gold leaf between two layers of glass; depending on the position of the thin layer of protective glass, called the “cover�, this mosaic may be used on floors or walls; the product code varies accordingly. Luminere (MOD) for wall coverings: the chip in which the gold is visible through the thin cover. Luminere (MOD) for floor coverings: the chip in which the gold is visible through the supporting layer of glass, with an effect of greater depth. Caution: in the case of the Luminere (MOD) mosaic with white gold leaf, only the floor-covering type must be laid immersed in water. Luminere (MOD) collection chips can be cut by hand when laying using the traditional artistic mosaic method, opus incertum and tessellatum, and to complete a running wall decoration.
** For further information contact the Grestec Tiles Technical Department. tel. +44 345 130 2241 mail@grestec.co.uk
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SPECIAL INSTALLATION JOBS: LOW WALLS & 90O CORNERS Covering these architectural features is simple. The mosaic may be mounted on mesh or paper, depending on the intended final use of the element.
INSTALLATION Check that the angle is vertical and perfectly perpendicular and that the substrate has been prepared correctly. Apply the adhesive and lay a sheet, or just a part of the sheet depending on the size of the low wall, on each side of the masonry feature. The adhesive must be prepared in strict accordance with the instructions on the label and applied evenly with the suitable spatula. For vertical surfaces, the final toothed trowel stroke must be horizontal.
FINISHING It is very important to keep the edges of the joints in the surfaces perfectly aligned. Adjust the chips for better results and then grout and clean the mosaic.
ROUNDING SHARP CORNERS Once the grout is completely dry, we recommend rounding sharp corners with a small angle-grinder with sandpaper discs in gradually decreasing grain sizes, from the coarsest (120) to the finest (360), or a diamond abrasive sponge.
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SPECIAL INSTALLATION JOBS: SHOWER TRAYS Customised wall coverings, finishing flush with the floor, for showers or bathtubs with a floor drain/ siphon outlet.
PREPARATION Prepare the substrate properly following the instructions for locations in direct contact with/ submerged in water. Then check the gradients and the concrete screed and that the waterproofing procedures have been carried out correctly. The way the mosaic is installed may vary depending on the type of drain outlet. Round drain: running or perpendicular installation Rectangular or square drain: installation perpendicular to the drain or the shower tray (if they are not perpendicular to each other).
PERPENDICULAR INSTALLATION After levelling the substrate, start laying one sheet starting from the shower tray drain outlet, regardless of its shape. Cut the sheet - or sheets - around the drain with pincers or an angle-grinder, bearing in mind that a row of chips with grouted joint will have to be laid around it. Start installing the cut sheets around the drain. Continue installing, laying the sheets one next to the other with a uniform joint size. To conclude glue a row of chips around the edge of the drain.
RUNNING INSTALLATION Cut the sheets into strips: for installation to the highest standards these must be just one chip wide. Start laying in concentric circles around the drain; shift the individual chips with a pointing trowel to obtain even joints. With chips of 20x20 it may be necessary to taper the chips in the strips closest to the drain.
FINISHING Leave a joint equal to that in the mosaic installed around the drain and then fill it, after grouting, with an elastic sealant suitable for the thermal expansion and contraction that will occur in the covering.
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SPECIAL INSTALLATION JOBS: STEPS Steps often have to be created, both indoors and outdoors, and in contexts in contact with or submerged in water. There may also be a stringer strip in a different colour.
PREPARING THE STRIPS OF MOSAIC CHIPS Prepare a sufficient quantity of strips of mosaic chips by cutting the mesh or paper on which the sheets are mounted. The chips must be mobile enough to allow them to fit around the rounded surfaces: to do this, reduce the amount of paper or mesh to the minimum required to hold the chips together. The rounding (r = radius) of the steps varies depending on the chip size and thickness and the mosaic mounting material; in general, this table applies:
MOUNTING MATERIAL
CHIP SIZE (MM) 10x10
15x15
20x20
ON MESH
r=30mm
r=35mm
r=50mm
ON PAPER
r=30mm
r=30mm
r=40mm
GETTING STARTED Before starting, always check that the substrate, adhesive and grout are suitable for the intended use, and level the steps so that they are perpendicular. Draw a line parallel to the top step: this will serve as reference when installing the first sheets.
INSTALLATION The entire mosaic can be installed by the running method or the techniques may be combined. In the first case, cut the mosaic into strips and lay it by fitting it onto the step. In the second case, only the rounded edge is covered by the running method, after which all the rest will be covered with mosaic laid perpendicular, cut to fit the last of the running strips. Start installing from the top of the step riser, level with the line you have drawn. Keep adding mosaic upward, using the strips or, depending on the curvature of the step, the cut, shaped individual chips. Then install the mosaic on the riser and start working downwards from the reference line. Lay a strip of chips at the end of the tread to form the outer edge of the step covering, and use a brush to apply the adhesive.
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SPECIAL INSTALLATION JOBS: STEPS ADJUSTING THE JOINTS Adjust the chips with a pointing trowel, making the joints as even as possible. Lay the strips of mosaic following the line of the mosaic already installed, starting first from one side and then from the other to alternate the strips for a more uniform final effect.
CUTTING AND SHAPING THE CHIPS With curved surfaces, you will have much smaller gaps between chips to fill: for a better appearance, in this case we advise you to remove a whole chip next to the empty space and replace it with two larger pieces cut to fill the whole of the gap. Use ordinary pincers for this kind of cutting job.
GROUTING AND CLEANING • Keep installing the mosaic, placing the strips of chips on the long side of the tread of the next step. • Repeat the same operation for the lower steps. • Then correct the joint sizes with a pointing trowel before the adhesive sets. • Grout the joints and clean as already described.
Adjusting the joints
How not to cut chips
The right way to cut chips
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SPECIAL INSTALLATION JOBS: BENCHES Benches, very popular in contact with water, are complex architectural features made up of several curved surfaces.
PREPARING THE STRIPS OF MOSAIC CHIPS Prepare a sufficient quantity of strips of mosaic chips by cutting the mesh or paper on which the sheets are mounted, as when covering steps.
GETTING STARTED When covering this type of complex feature, the surface must be smooth and even, with a levelled cement mortar substrate suitable for the intended use. Mark perpendicular lines on the back of the bench and install two rows of chips next to them; they form the main locator markers. In general, for complex curves, this table applies:
SUPPORT
CHIP SIZE 10x10mm
15x15mm
20x20mm
MESH-BACKED
r = 50mm
r = 50mm
r = 80mm
PAPER-FACED
r = 50mm
r = 50mm
r = 80mm
INSTALLATION
Start from a corner, always laying one horizontal and one vertical strip of chips, following the reference grid. Keep installing horizontal strips, using a pointing trowel to adjust the position of the chips and following the form of the curved surface. To soften the mounting paper, wet it with a wet sponge. Complete covering the back in this way. Lay more locator strips on the seat and continue installing the mosaic on the new grid.
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SPECIAL INSTALLATION JOBS: ROUND EDGES Architectural features of this kind are often used as urban furnishings or in swimming-pools and spas.
PREPARING THE STRIPS OF MOSAIC CHIPS Prepare a sufficient quantity of strips of mosaic chips by cutting the mesh or paper on which the sheets are mounted, as when covering steps.
GETTING STARTED Check that the surface is smooth and even, with a levelled cement mortar substrate suitable for the intended use. Draw a vertical line passing through both sides of the feature. Using this as reference, install the first two sheets across the rounded surface; they become your locator marks.
INSTALLATION Carry on installing the sheets underneath and then beside the first two, keeping them perpendicular to the rounded edge. Also cover the sides of the backrest, adjusting the chips if necessary. On rounded backrests, install a row of chips on the outer edge and then start running installation, applying precut strips of mosaic and fitting individual chips shaped with ordinary pincers where necessary. Remember to make sure that there are no sharp edges on hand-cut chips by smoothing them with sandpaper or a diamond disc.
ADJUSTING JOINTS Gradually adjust the joint sizes with a pointing trowel before the adhesive sets. Grout the joints and clean as already described.
Drawing the reference lines
Installation
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SPECIAL INSTALLATION JOBS: SHELL A shell is a rounded connection between perpendicular surfaces; it is used to cover concave features such as pools.
GETTING STARTED Check that the corners are perfectly perpendicular and rounded and have a levelled cement mortar substrate suitable for the intended use. We recommend the use of paper-mounted mosaic. First, place a sheet dry on the two vertical surfaces that form the angle and measure the number of chips included in the rounded part.
REMOVE THE SURPLUS CHIPS Now cut a square of chips, of the same size as those measured, from the middle of the bottom of the sheet. Put the sheet back over the angle, placing the two edges formed by cutting out the block against each other, low down on the bottom of the concave form to be covered.
INSTALLATION Adjust the position of the sheet by drawing a horizontal line with the spirit level, and then use the laser to create a grid that will serve as reference for the other sheets to be installed. Apply the adhesive and install the sheet you have cut in the form of an upturned U; continue installing horizontally to the left and right and then gradually working upwards. Keep on along the walls, placing the new mosaic next to the sheets already installed and keeping the joints aligned.
THE SHARP EDGE Finally cut the chips which are to form the sharp edge to size with pincers or an angle-grinder with diamond disc. Remove the paper and adjust the chips and then proceed with grouting and cleaning
Drawing the reference lines
Installation
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SPECIAL INSTALLATION JOBS: SWIMMING POOLS SUBSTRATE PREPARATION The substrate is the layer or complex of layers between the load-bearing structure and the surface for covering. The most important phase is the removal of all flaws; structural steel members must be coated with rustproof products and treated with cement mortars. We recommend removing residues of release agents or similar products with steel brushes, an anglegrinder or granular soda in a 5% solution. If possible, apply a levelling mortar to round off all the sharp edges, depending on the size of the mosaic to be installed. The site must be protected from rain and sun, including after installation, for long enough to allow the grout to cure completely. Check the humidity level of the substrate and structure, which must not exceed 3% once curing is complete; otherwise, further shrinkage may occur as they dry, causing cracking. The work site temperature must be between 10 and 30°C to allow the correct preparation and application of the installation products.
INSTALLATION Mosaics are installed in swimming-pools in exactly the same way as on ordinary surfaces.
SWIMMING-POOL MAINTENANCE During the winter, the pool should not be emptied but the water level should be kept 15-20 cm below the overflow so that the treatment system and filters remain dry. In particularly hard winters the pumps should be run to circulate the water; otherwise, floats of easily compressed material should be placed halfway around the edge to minimise the effects if the water freezes.
Rounding corners with levelling cement
Removing metal parts